The effects of cosmic radiation on pocket mice aboard Apollo XVII: V. preflight studies on tolerance of pocket mice to oxygen and heat. Part IV. observations on the brain.

Experiments designed to ascertain the effects of oxgen at 8, 10, and 12 psi partial pressure on the brains of pocket mice (Perognathus longimembris) were carried out at room temperature (24 degrees C, 75 degrees F) and at 32 degrees C (93 degrees F). The animals exposed to 8-12 psi at 32 degrees C had been in earlier KO2 oxygen tests. Five animals exposed either to 10 or 12 psi (517 mm or 620 mm HG) PO2 at 32 degrees C died during the course of the tests, possibly as a consequence of injury sustained by the earlier PO2 testing. Autopsy was not carried out. In the other 36 exposed animals, no pathological changes were observed in the brain. It is thus highly probable that oxygen pressures at the hyperbaric levels to which the pocket mice would be exposed during the Apollo XVII mission would not result in any lesions in the brain.

Human factors for capacity building: lessons learned from the OpenMRS implementers network.

OBJECTIVES: The overall objective of this project was to investigate ways to strengthen the OpenMRS community by (i) developing capacity and implementing a network focusing specifically on the needs of OpenMRS implementers, (ii) strengthening community-driven aspects of OpenMRS and providing a dedicated forum for implementation-specific issues, and; (iii) providing regional support for OpenMRS implementations as well as mentorship and training. METHODS: The methods used included (i) face-to-face networking using meetings and workshops; (ii) online collaboration tools, peer support and mentorship programmes; (iii) capacity and community development programmes, and; (iv) community outreach programmes. RESULTS: The community-driven approach, combined with a few simple interventions, has been a key factor in the growth and success of the OpenMRS Implementers Network. It has contributed to implementations in at least twenty-three different countries using basic online tools; and provided mentorship and peer support through an annual meeting, workshops and an internship program. The OpenMRS Implementers Network has formed collaborations with several other open source networks and is evolving regional OpenMRS Centres of Excellence to provide localized support for OpenMRS development and implementation. These initiatives are increasing the range of functionality and sustainability of open source software in the health domain, resulting in improved adoption and enterprise-readiness. CONCLUSIONS: Social organization and capacity development activities are important in growing a successful community-driven open source software model.

Affinity labels for the anion-binding site in ovotransferrin.

Bromopyruvate, a known alkylating agent, has previously been reported to function as an affinity label for the anion-binding site in the iron-binding protein ovotransferrin [Patch, M.G., & Carrano, C. J. (1982) Biochim. Biophys. Acta 700, 217-220]. However, the present results indicate that hydroxypyruvate also functions in an almost identical manner, which implies that alkylation of a susceptible nucleophile cannot be the mechanism responsible for the covalent attachment of the anion. Model complexes and amino acid analysis of labeled ovotransferrin suggest that initial Schiff base formation, followed by reduction of the imine bond between the affinity anion and a lysine within the locus of the anion-binding site, accounts for the irreversible labeling. As expected, the covalently attached anions render the iron in the ovotransferrin-iron-anion ternary complex much more resistant to loss at low pH. It is proposed that the covalently labeled protein be used to test the hypothesis that iron removal from transferrin occurs by protonation and loss of the anion in low-pH lysosomal vesicles.

Effect of a covalently attached synergistic anion on chelator-mediated iron-release from ovotransferrin: additional evidence for two concurrent pathways.

The mechanism by which the iron-transport protein transferrin releases its iron in vivo is presently unclear. In vitro studies have implicated two concurrent chelator-mediated iron-release pathways: one which is hyperbolic in nature, involving a conformational change in the protein as a rate limiting step, and a second which has been proposed to be first-order in nature and to involve initial release of a synergistic anion. We have examined the effect that an affinity-label analog of the synergistic anion has on chelator-mediated iron-release from this protein. A covalently attached anion would inhibit iron-release via any pathway in which anion release is a prerequisite to iron release. The present investigation examined the effect that the covalently attached anion had on iron-release to pyrophosphate (PPi) and N, N-bis(phosphonomethyl)glycine (DPG), two chelators which are believed to utilize both pathways concurrently. Results show that when the affinity-label anion is utilized, strictly hyperbolic data are obtained, with similar observed kmax values. This is strong support for the hypothesis of a common, chelator-independent rate-limiting step for the one available pathway. These results also support strongly the hypothesis that synergistic anion removal is a prerequisite step to iron-release via the second pathway.